DISCOVERY OF FERMENTATIVE ORGANISMS. 3 



world has entitled him " the father of micrography," i.e. that 

 science which treats of the most minute forms of life. 



This newly-discovered field of research was at first regarded 

 by Leeuwenhoek's successors from an almost exclusively medical 

 standpoint, as it is a natural instinct in man to try and maintain 

 health and to prevent disease. At that particular period, too, a 

 special impetus was given to the study of medicine by the ravages 

 of the plague, which only too frequently pursued its destructive 

 course throughout Europe. 



On the other hand, the study of the phenomena of fermenta- 

 tion derived little or no benefit from Leeuwenhoek's discovery. 

 The first investigator whom we meet with in this domain is the 

 Viennese physician, Marcus Antonius Plenciz, who in his work 

 "Opera medico-physica" issued in 176^2, applied the results of 

 Leeuwenhoek's discoveries, not only to the field of medicine, 

 but also to that of fermentation and putrefaction. In the latter 

 connection he arrived at the noteworthy conclusion that " a body 

 undergoes putrefaction when the germs of vermicular creatures 

 begin to develop and multiply ; because these animals excrete 

 numerous precipitatiops consisting of volatile salts, by which the 

 liquids are rendered turbid and malodorous." 



However alluring a closer acquaintance with these minute 

 creatures may have been to the investigators who succeeded 

 Plenciz, and however useful, from a practical point of view, might 

 be to observers the processes of decomposition which they induced, 

 these questions were nevertheless forced temporarily into the back- 

 ground by another, namely, the origin of these minute organisms. 



How do the minute creatures so copiously developed in infusions 

 originate ? 



Some opined that these organisms were produced from certain 

 unorganised (and therefore inanimate) substances, chemical com- 

 pounds, present in the liquid in question, their formation being 

 therefore considered as spontaneous (generatio spontanea), or 

 arising from elementary substances (primary generation). Or, 

 whilst proceeding from elementary substances, as differing there- 

 from (heterogeneous), or dissimilar thereto (equivocal) ; hence the 

 name Heterogenesis or generatio cequivoca : all of which terms, 

 as well as that immediately to be noted, have the same import. 



The party opposed denied, on the other hand, the possibility of 

 a transition from a lifeless to a living condition (abiogenesis), and 

 asserted that when "infusoria" are detected in an infusion, a 

 liquid or matter undergoing decomposition, their existence is due 

 to living germs present therein. 



Which view is correct ? On this point there arose, about the 

 middle of the eighteenth century, what formed one of the live- 

 liest disputes agitating the domain of natural science at that period, 

 and which, after occupying the most earnest attention of several 

 successive generations of scientists, only terminated, after nume- 



